High temperature alloys mean a class of metal materials which can work at a high temperature of above 600° C. and at a certain stress for a long-term. High temperature alloys generally include iron-based high temperature alloys, nickel-based high temperature alloys, cobalt-based high temperature alloys, etc. High temperature alloys have relatively high strength at a high temperature, good resistance to oxidation and thermal corrosion, excellent fatigue performance, fracture toughness, plasticity, and other properties. High temperature alloys also have good structure stability and application reliability at various temperatures. On the basis of above properties and characteristics, high temperature alloys exhibit a high alloying extent, and thus are also called as Superalloys.
High temperature alloys have been used in many industrial field, such as large aircraft engineer—as materials of components at hot end of aircraft engine; Industrial gas turbine—as materials for hot end components; nuclear power technology—as tubes of high temperature alloys; other civil industries -metallurgies, petrochemistries, transportations, and energy sources, etc.; aircraft engines—as high strength high temperature alloys; aerospace engines—as short-term ultrahigh temperature high strength high temperature alloys; marine engines—as high temperature alloys having corrosion resistance and long life.
High temperature alloys generally consist of a plurality of alloying elements, and all the alloying elements such as Ni, Mo, Nb, Cr, etc. required for the manufacture of high temperature alloys at present are substantially pure elemental substances. However, in the domestic and international markets, due to the high prices of pure metals, the manufacture cost of high temperature alloys is relatively high. However, as to specific products, metallic raw materials with high purities are unnecessary. Since there are not raw materials with proper quality in the market, downstream enterprises have to purchase “over-qualified” raw materials, the cost for raw materials is increased. If a specific base alloy material, which is not elemental substance, is produced according to specific alloy products, then the purchase cost will be reduced greatly. For producers of raw materials, the production costs will also be reduced remarkably and thereby the market competitiveness will be improved.
At present, high temperature alloys and the base material thereof are melted in electric arc furnace, vacuum induction furnace, or by electroslag remelting, or a combination thereof. These melting apparatus and methods are main melting forms employed in the world. Hence, it is desired to remarkably reduce the production cost of high temperature alloys and not increase the apparatus investment, and at the meanwhile ensure the uniformity of the alloy components. Moreover, the high temperature alloys produce by utilizing such base material achieve equivalent or better properties as compared to the same class of alloys.